ABT-229 is a new drug that belongs to the class of macrolides with motilin agonist activity and without significant antibotic activity. Treatment of diabetic gastroparesis with motility agents have met with some success. ABT-229 has the potential to alter the pathophysiology and improve the symptoms in patients with diabetic gastroparesis without altering the normal gut flora. The objectives of this study are to assess the efficacy of four different doses of ABT-229 compared to placebo for the treatment of postprandial digestive symptoms and to assess the safety of ABT-229 in patients with insulin-requiring diabetes.